获取centos外网ip

public static String getIp(){
    Enumeration<NetworkInterface> nis;
    String ip = null;
    try {
        nis = NetworkInterface.getNetworkInterfaces();
        for (; nis.hasMoreElements();) {
            NetworkInterface ni = nis.nextElement();
            Enumeration<InetAddress> ias = ni.getInetAddresses();
            for (; ias.hasMoreElements();) {
                InetAddress ia = ias.nextElement();
                //ia instanceof Inet6Address && !ia.equals("")
                if (ia instanceof Inet4Address && !ia.getHostAddress().equals("127.0.0.1")) {
                    ip = ia.getHostAddress();
                }
            }
        }
    } catch (SocketException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return ip;
}